The Practicality of Ontology

How does ontology and presumptions about it impact our daily lives in a way that we might not expect or appreciate? Yeah, I think there are probably a couple easy strands to map out there. The most obvious is probably bioethics or medical ethics. So let's say you have a loved one who has rendered, you know, brain dead or is put in medically induced coma. Are they still a lot? And do they have certain rights and how should we interact with them?